31-12-2010, 01:56 PM
SUBIMITTED TO:-
ms. Neelam Arya
Deptt. Of EC
ITM GWALIOR
SUBIMITTED BY:-
Rajendra ku. Bansal
[attachment=7800]
Why CDMA?
CDMA is extremely robust and provides excellent audio quality
CDMA is the technology of choice for both 800 MHz Cellular and 1900 MHz PCS service providers
CDMA satisfies CTIA Users’ Performance Requirements
CDMA provides high capacity (many times the capacity of AMPS)
CDMA provides privacy through its coding scheme
What is Multiple Access?
Multiple Access: Simultaneous private use of a transmission medium by multiple, independent users.
Since the beginning of telephony and radio, system operators have tried to squeeze the maximum amount of traffic over each circuit
Types of Media
Twisted pair - copper
Coaxial cable
Fiber optic cable
Air interface (radio signals)
Advantages of Multiple Access
Increased capacity: serve more users
Reduced capital requirements since fewer media can carry the traffic
Decreased per-user expense
Easier to manage and administer
Each pair of users enjoys a dedicated, private circuit through the transmission medium, unaware that the other users exist.
Multiple Access Technologies
Channel: An individually-assigned, dedicated pathway through a transmission medium for one user’s information
The physical transmission medium is a resource that can be subdivided into individual channels according to different criteria depending on the technology used:
Here’s how the three most popular technologies establish channels:
FDMA (Frequency Division Multiplex Access)
each user on a different frequency
a channel is a frequency
TDMA (Time Division Multiplex Access)
each user on a different window period in time (“time slot”)
a channel is a specific time slot on a specific frequency
CDMA (Code Division Multiplex Access)
each user uses the same frequency all the time, but mixed with different distinguishing code patterns
a channel is a unique set of code patterns
ms. Neelam Arya
Deptt. Of EC
ITM GWALIOR
SUBIMITTED BY:-
Rajendra ku. Bansal
[attachment=7800]
Why CDMA?
CDMA is extremely robust and provides excellent audio quality
CDMA is the technology of choice for both 800 MHz Cellular and 1900 MHz PCS service providers
CDMA satisfies CTIA Users’ Performance Requirements
CDMA provides high capacity (many times the capacity of AMPS)
CDMA provides privacy through its coding scheme
What is Multiple Access?
Multiple Access: Simultaneous private use of a transmission medium by multiple, independent users.
Since the beginning of telephony and radio, system operators have tried to squeeze the maximum amount of traffic over each circuit
Types of Media
Twisted pair - copper
Coaxial cable
Fiber optic cable
Air interface (radio signals)
Advantages of Multiple Access
Increased capacity: serve more users
Reduced capital requirements since fewer media can carry the traffic
Decreased per-user expense
Easier to manage and administer
Each pair of users enjoys a dedicated, private circuit through the transmission medium, unaware that the other users exist.
Multiple Access Technologies
Channel: An individually-assigned, dedicated pathway through a transmission medium for one user’s information
The physical transmission medium is a resource that can be subdivided into individual channels according to different criteria depending on the technology used:
Here’s how the three most popular technologies establish channels:
FDMA (Frequency Division Multiplex Access)
each user on a different frequency
a channel is a frequency
TDMA (Time Division Multiplex Access)
each user on a different window period in time (“time slot”)
a channel is a specific time slot on a specific frequency
CDMA (Code Division Multiplex Access)
each user uses the same frequency all the time, but mixed with different distinguishing code patterns
a channel is a unique set of code patterns
